Dr. Rebecca A. Peebles - Assistant Professor, Department of Chemistry

Uploaded by catsEIU on 10.05.2012

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My name is Rebecca Pebbles and I'm an associate professor
of chemistry here at Eastern Illinois University.
I've been doing research in the chemistry department with my
husband Sean Pebbles who is also a chemistry faculty for about
the last 3 1/2 years using support that we've gotten from
the National Science Foundation, and that support has allowed us
to include a whole bunch of students in our research
and also to build some new unique equipment that we
wouldn't have been able to construct at EIU otherwise.
Sean and I are physical chemists which really means that instead
of being interested in what exact chemical reactions happen,
or doing chemical reactions, what we're doing is answering
questions that begin with why or how.
So for instance a question which is actually related to our
research is why have some general anesthetics been linked
to an increased risk of Alzheimer's disease.
What we do actually is really fundamental research so we are
looking for an inproved understanding of properties,
of chemicals, and a way that chemicals behave which then
can let other researchers later on do things like find better
ways to build nano scale, tiny microscopic circuits, to come up
with improved drugs that work better and have fewer side
effects, and all sorts of other things that we may not have
ever thought about yet.
The question that we're looking to answer in our own research
is why do certain chemicals specifically interact with each
other the way that they do and not in some other way.
The way we're answering these questions at Eastern Illinois
University is using a relatively new technique called chirped-
pulse, fourier, transform, microwave, spectroscopy,
which we shortened to CPFTMW.
We have used our funding from the National Science Foundation
to actually build from scratch a CPFTMW spectrometer in our lab
at EIU and that spectrometer we're pretty proud of it
and it's still one of about 10 to 15 of these instruments
in the entire world.
The instrument was built by Dan Obencsheim, who you can see
actually working and using it in the picture here and it relies
on squirting a gas through a very tiny hole and then shining
microwaves just like you would have in your microwave oven at
that gas and seeing what types of microwaves are absorbed.
Another thing we rely on a lot is actually zapping the
chemicals with an electric current to form very unstable
reactive species, like you might find in the upper atmosphere
or in a flame or in a car engine, so we can try
to understand how those behave as well.
When we look to observe what types of microwaves a particular
chemical absorbs, we get something called the microwave
spectrum which is really just sort of a chart which you can
see here of what frequencies are or are not absorbed
by a molecule.
But this chart is actually pretty much a unique fingerprint
for a particular molecule and for a particular orientation
of molecules.
So, by looking at the spectrum or chart that we get out for
a particular system, we're able to completely unabiguously
figure out which of our many, many possible structures
is the true structure for this molecule or pair
of molecules together.
We've actually studied a whole bunch of these now and what
we're trying to do is build up patterns to make it easier
to predict without doing the experiment how these things
will behave because if we know ahead of time how the chemicals
will behave then people like the engineers who want to use that
knowledge for something else to build new circuits, to build new
drugs or something like that, will have a much easier job
in the future.
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